Iron ore can be reduced by feeding the ore in powdered form together with a powdered solid or liquid carbonacous reducing agent, into a reaction zone maintained at a temperature high enough to cause a substantial instantaneous reaction between the oxide and agent. The reaction is endothermic and requires a continuous supply of heat.
One proposal has been to use a shaft furnace charged with a coke column. To supply the necessary heat it was thought that a plasma burner might be installed in the furnace side above the hearth to provide the reaction zone in the coke. This proposal was never reduced to practice insofar as is known.
On the other hand, melt reduction is a practical process. It comprises the use of a DC arc furnace in which a carbonacous iron melt is maintained and into which the ore and agent are fed at the foot of the arc.